Karthus Build Guide

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Nukin' Karthus

written by SubtleWrath

Karthus Build

Table of Contents

  • Introduction

    Hey , lately ive seen some really poor karthus' in game and i wanted to just show everyone the kind of build i use, its probably not the best build you'll ever see but i think it covers some important points :)
    this is my first guide so i hope you guys find it helpful

  • Abilities

    Death Defied
    Great passive for team fights, and the CD on death is nice too more about this a little later

    Lay Waste
    Karthus' bread and butter, a little difficult to hit well with for begginers, but with practice can be an amazingly OP skill.

    Wall of Pain
    Probably the best spell on Karthus, a skill that reduces MR,Armor and slows for 80%? yes please

    Amazing Spell, an AOE DPS that is kinda like a mini infinate crowstorm, the passive is great early game too :)

    probably Karthus' least impressive spell :P. the skill in using requiem is simply knowing when to use it, more on that a little later

  • Masteries + Runes

    i go for 10/0/20 on karthus, pretty much standard caster except with an additional point in offensive on the ignite cooldown

    for runes i use-

    3 x Greater Quintessence of Force
    9 X Greater Mark of Insight
    9 X Greater Seal of Replenishment
    6 X Greater Glyph of Force
    3 X Greater Glyph of Focus

    However pretty much any Rune build is viable as long as you keep the 9 x magic pen runes

  • Play Style

    Early game-

    Before the game starts look at how many people have heal. If you don’t you may regret it, try and keep tabs on who has used it, write it down if necessary.

    Use LW to farm minions as much as possible, but don’t overdo it you don’t want to burn yourself out of manna before getting to around 6/7, harass your enemy in the lane using LW, to do this try to predict their movements, usually placing the spell slightly behind them will work as most will try to move back when they see your staff go up but it can vary, study your enemy.

    Harass them but don’t play too overly aggressive and try to get the kill when its not there, just keep aggravating, deny them XP and try to keep their health down, of course if they are asking to be killed do it but don’t make a bad call and end up having to go back to base again within the first couple of levels-this is really bad for karthus-. If you’ve been harassing enough by level 6 your opponent should hopefully be down enough to use your ult right away, if not and your harassing has done no good or there just good at regen/heal look to other lanes and assess whether your ult may help any of your teammates.

    -Note- A good Karthus is always looking at other lanes and at other enemies and their abilities, always assess who can block your ult, if they have used it, when they used it and the MR they have. Sorry but if you suck at quick mental maths, don’t play karthus. Once your ult is up you need to very quickly be able to calculate how much pen you have and how much damage you will inflict with it, if you can’t do this your gonna waste a lot of ults, this is even more important late game when people start getting MR items and veil etc.

    Mid to late-

    Stick in your lane to your about level 11, if you haven’t already grab the blue buff, the manna regen and CDR will really help and if nobody else has bothered yet grab the red as well (ask before you do though, other teammates can benefit more from it that you)

    From there on go either top or bottom depending on where you think you make the most difference and try and help the team move forward.

    When a gank is iniated try and land your wall straight away preferably before they have seen you and rush in with defile and LW, if your teammates help you should quite easily be able to score a few kills or push them back and maybe get a tower. Usually if you’re playing right or there just terrible they will surrender about this sorta time, if not its highly possible that they will start stacking MR to try and counter you, this is around the time you want to start building a void staff.

    In team fights it’s pretty much the same process as ganking try and hit as many as you can with the wall then use defile and lay waste to pick them off. Never go in before the tank, you will get ripped apart and most half intelligent teams know enough to move away from your corpse. If your using the Mejai’s the team will start to focus on you first during team fights if this happens try to kite them as much as possible using LW and defile, let your team focus and bring them down or wait until you’ve brought them down enough then turn round and nuke em’

    Karthus is really really bad at destroying stuff unless you have lich bane or something, try to avoid having to destroy towers by yourself.

    Using Requiem-

    Believe it or not does more than KS ;)

    -Early on use it as a way of catching runners and tipping the balance of fights in favour of your allies

    - Once you have accumulated some AP start using it before you gank or before team fights if it’s that far ahead OR wait until your team has brought the enemy team down them all to respawn out into lanes and then use it. Force them to go back to heal and gain a couple more seconds hacking down towers and gaining XP :).

    -Just because you can’t see them doesn’t mean you can’t kill them. If you see an enemies hp then they disappear, quickly run through what they can do, items etc if you think your clear hit them with it, if not hold it back, if someone wanders off with a shield like lee sin, blitz etc, count to about 6-8 seconds then hit it, chances are the shield has dissipated and you catch them just are they are porting.
    Why 6-8 you ask? It takes 8 secs to port and 3 secs for you to ult, however it’s very rare that they will simply port right after they leave your vision and even rarer that they will pop a shield of some sort as soon as they do, usually they spend a couple of extra seconds just running.

    When to die-

    Preferably never. However sometimes in team fights you may be able to take out 3 or 4 people if you can just get enough time and manna to use requiem , this is the time you want to rush in and let them focus on you, once you’re dead you pop on defile Immediately and cast requiem (only if you’re going to get kills). The general rule of thumb is don’t do it if you don’t think you can get more than 2 people, its not worth the money they will gain from killing you and if your stacking Mejai’s it can be annoying to lose some stacks then not manage to get the kill.

    Note- don’t start doing this till the mid to late stages of the game, early on it probably wont work

  • Items

    well first off i always start off With a Sapphire Crystal and one Health Potion and one Mana Potion

    After laning for a while and possibly a few kills at about level 6-7 you should have enough for a Ruby Crystal and Boots of Speed

    After that try to get the Catalyst the Protector and a Blasting Wand to get a
    Rod of Ages asap, once you have this it shouldn’t be long before you can cough up another 750 to get the Sorcerer's Shoes and a start to build up a Mejai's Soulstealer.

    The beauty of the build is that after you have the ROA, the ss and Mejais should be relatively quick to build considering the relative price comparative to other similar items, and provided you get a decent amount of kills the Ap should keep up too.

    If you don’t feel confident you can nail the kills with the mejai or you think you may die a little too often for it to be of any major use to you try building another survivability item so you can stay out on the field a little longer and hopefully accumulate a little more XP.

    By the time you next come back to the shop to buy you should be well into the midgame, at this point you need to consider how your opponents are reacting to you, if they are ignoring you start to build an Archangel's Staff, if they are starting to stack some MR build a Void Staff.

    i tend to finish off my build with a Rabadon's Deathcap however few games are that simple.

    here are a few items that i found very helpful on Karth in certain situations-

    Rylai's Crystal Scepter
    Amazing item for Karth, what? everyone has freaking boots of mobility? get one of these and bring them all down a notch, also synchs great with your wall and if you kiting someone. the health boost is pretty darn lovely as well ;)

    Lich Bane
    Awesome item on Karth, Basically turns you into a physical threat as well, ans lets you kick out just that little bit more dps. also makes karth take down structures a lot lot quicker

    Abyssal Scepter
    A good item if the enemy team really is piling on the MR, in that sort of situation consider switching out the mejai for this item, because of the situation you arnt going to get massive amounts of kills unless you get close and personal anyway. the good thing about this item is its an aura so your teammates will benifit too. you also get a nice boost to your own MR which is very nice :)

    Ok and just to clear this up with all the mindless AP stackers out there incase i get lots of 'hey you can get more AP if you do this'. you dont actually do more damage if you just stack AP :/, infact you end up wasting a lot of that AP you spent lots of gold on-

    100 MR example (50% resist)-

    1400 AP karthus(5 AA +rabadons)-

    Requiem damage- 1548
    Against 100 MR
    Base penetrations (if same masteries and runes are used)- 100-9(runes) =((91/100)*85) (mastery)
    Overall drop from 50% to 46%
    ((1548/100)*54)= 835 damage
    AP wastage- 459 (45%)

    900 AP (My build)-

    Requiem damage- 1184
    Against 100 MR
    Base And Item penetrations- 100-29(sorc shoes+runes) = ((71/100)*51) (mastery+ void staff)
    Overall drop from 50% to 26%
    ((1184/100)*74) = 876 damage
    AP wastage- 164 (25%)

    Bare in mind that 100 MR is pretty generous, most games where karthus becomes a real threat it can get a lot higher rendering mindless Ap stacking completely pointless.

    Im aware that even with this build it is possible to have more Ap without sacrificing the magic pen ,probably another 100 or so, however you would be giving up on the survivability and (if your good) the 15% CDR you gain from mejai’s when fully maxed out, which in my opinion isn’t worth the risk.

    Don’t underestimate your ability as a DPS mage, when fully maxed out you can do about 2000 dmg/sec (subject to reduction ofc) which means most squishys that don’t stack MR go down in about a second when they 1v1 karth, HOWEVER your biggest vulnerability is stuns and suppressions ,if you can’t attack for a couple of seconds, your dead, so take care when singling out an opponent and don’t try and solo the enemy team very late game (40+ mins), it wont work.

  • Summoner Spells

    Im pretty boring with my spell selection, i tend to pick Ignite and Heal

    Ignite is a pretty obvious choice, it keeps healers at bay and early on its great if the person your laning agaisnt is trying to pop a health potion to try and stick it out a bit longer against you. i would recommend using it to any karthus player as your worst enemy is healing.

    I use heal because i find that early on it can make the difference between getting a kill and not getting one or gaining a few extra levels before you have to go back to base, also its great late game where your in a 1v1 and it just tips the fight in your favour. i know its nooby but heal is a winner

    other great spell choices-

    not a personal favourite as i tend to be able to manage my mana fairly well but good if you play very aggresively early on

    Gets you back to farming quicker. simple as that. again i dont tend to use it but i can see why some people do

  • Skilling Order


    I find that early leveling of defile really helps me early game, although leveling wall of pain up early can be just as useful, the only essentials of the skill order is LW AND Requiem.

  • Pros / Cons

    - Insane Dps when used correctly
    - Powerful global nuke
    - Easily catch runners with ultimate
    - massively damaging to enemy team morale
    - WOP makes EVERYONE do more damage
    - Excellent Ganker

    - even with good survivability items your still very squishy
    - slow
    - both teams will hate you

  • Summary

    To sum up karthus is an incredably powerful caster, but everyone will play him slightly differently if you feel there are parts of the build that dont work for you change the build to fit your style, hell if you wanna stack AA and run in and suicide do it, this is just my way of playing him.

    thanks for reading :)

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Submitted by SubtleWrath

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